【作者】 江天；

【导师】 程湘爱；

【作者基本信息】 国防科学技术大学 ， 光学工程， 2012， 博士

【摘要】 随着光电探测器在军事和民用等诸多领域的广泛应用，半导体光电探测器的激光辐照效应越来越受到人们的重视。光电探测器的种类繁多，每种探测器都有其特定的光谱探测范围，即存在探测的截止波长。在实际的光电对抗中，对探测器进行干扰和损伤的激光波长不一定恰好位于探测器的响应波段内，本文将光子能量大于探测器材料禁带宽度的激光称为该探测器的波段内激光；把光子能量小于探测器材料禁带宽度的激光称为该探测器的波段外激光。本文以光伏（PV）型和光导（PC）型单元光电探测器为研究对象，分别在实验和理论上系统地研究了PV型探测器和PC型探测器在波段内激光辐照下的非线性响应机理以及在波段外激光辐照下的响应机理。研究内容如下：1．研究了PC型探测器在波段内连续激光辐照下动态响应的物理过程。进行了PC型InSb红外探测器的波段内激光辐照实验，建立了PC型探测器在波段内连续激光辐照下的载流子输运模型，数值计算结果与实验结果吻合，分析了PC型探测器在波段内激光辐照下的响应机制。研究表明，PC型探测器对波段内激光的响应机制包括光激发载流子效应和热效应，热效应主要体现为温度对载流子迁移率的影响和温度对载流子浓度的影响。在分析PC型探测器在波段内激光辐照时的电压信号时，必须考虑以上三种效应对输出电压信号的影响。2．系统地研究了PV型探测器在波段内连续激光辐照下非线性响应的物理机制。在大量实验的基础上，明晰了PV型探测器在强光辐照下的一般规律性现象，和由探测器个体差异导致的特殊现象。发现并对比研究了两种典型的过饱和现象，理论上，从等效电路模型出发，分析了两种过饱和现象的发生条件，建立了数值计算的理论模型，对两种过饱和现象进行了数值模拟，计算结果与实验结果吻合得较好。研究表明，PV型探测器在波段内激光辐照下引起的过饱和现象有两种产生机制，一种是热效应引起的暗电流增大机制；另一种强光引起的漏电流增大效应，该机制是由于探测器材料制备过程中引入缺陷导致的。3．系统地研究了PC型探测器在波段外连续激光辐照下动态响应的物理过程。实验上，分别进行了PC型InSb和HgCdTe两种典型红外探测器的波段外激光辐照实验，发现了一种普遍存在于PC型探测器在波段外激光辐照下的新现象，深入分析了新现象的产生机理。建立了PC型探测器在波段外连续激光辐照下的载流子输运模型，分析了PC型探测器在波段外激光辐照下电压响应的机制，数值计算结果与实验结果吻合。研究表明，PC型探测器对波段外激光有响应，其响应机制仅为热效应，具体表现为温度对载流子迁移率的影响和温度对载流子浓度的影响。波段外激光辐照下，探测器温升，当探测器芯片温度小于特征温度（电导率出现极小值时对应的温度）时，温度对载流子迁移率的影响起主导作用，探测器的输出电压信号表现为随温度升高而增大；当探测器芯片温度大于特征温度时，温度对载流子浓度的影响起主导作用，探测器的输出电压信号表现为随温度升高而减小。探测器输出电压信号是由温度对载流子迁移率的影响和温度对载流子浓度的影响共同决定。4．研究了PV型探测器对波段外激光的响应机制，研究表明，热生电动势为PV型探测器对波段外激光响应的主要机制，并阐明了不同初始开路电压条件对探测器输出信号的影响。利用Si太阳能电池重现了HgCdTe探测器在波段外激光辐照下的实验现象，并围绕着热生电动势是否存在、与光生电动势的区别与联系以及与温差电动势的区别等问题设计了实验，从实验的角度验证了热生电动势的正确性。更多还原

【Abstract】 With the widespread use of photoelectric detectors in different aspects, especiallyfor military and civil purpose, more and more attentions are being paid to the irradiationeffects of semiconductor materials and photoelectric detectors. There are kinds ofphotoelectric detectors. However, for a specific detector, it could only response to aspecific spectrum range. In other words, every kind of detector has a cut-off wavelength.In the practical photoelectric confrontation, the lasers, which are adopted to disturbphotoelectric detectors, are probably not in the spectrum range of the photoelectricdetector. In this paper, we call the laser above-band gap laser, whose photon energy islarger than the band gap energy; otherwise call it sub-band gap laser.In this paper, the photovoltaic (PV) detectors and photoconductive (PC) detectorshave been taken as the investigated subjects. The nonlinear response mechanisms of PVdetectors under above-band gap laser radiation and response mechanisms of PCdetectors under sub-band gap laser radiation are carefully investigated. The investigatedcontents are as follows:1. The dynamic response physical process of PC detectors under above-band gaplaser radiation is investigated. The above-band gap laser irradiates the PC InSb detectorsin experiment. The carrier transport model of PC detector under above-band gap CWlaser radiation is established. The calculation results agree well with the experimentalresults. The response mechanism of PC detector under CW laser radiation is analyzed.It’s shown that the response mechanism of PC detector under above-band gap laserradiation is composed of optical excited carriers and thermal effects. The thermal effectsinclude temperature-dependence mobility effect and temperature-dependence carrierconcentration effect. When the voltage signals of PC detector under above-band gaplaser radiation are analyzed, the above three effects must be considered.2. The nonlinear response physical mechanisms of PV detector under above-bandgap laser radiation are carefully investigated. Based on many experimental results, theregular phenomena of PV detector under intense light radiation and specific phenomenainduced by individual difference are definite. Two typical over-saturation processes arediscovered and investigated. In theory, the generation conditions of the two typicalover-saturation processes are analyzed from the equivalent circuit model. The numericalcalculation model is established, and the two kinds of over-saturation processes arenumerical simulated. The numerical results and experimental results are in goodagreement. It’s shown that two generation mechanisms of the over-saturationphenomena of PV detector under above-band gap laser exist. One is increased darkcurrent due to thermal effect. The other is leak current due to intense light radiation. Theleak current is caused by the bugs, which are formed during the preparation process. 3. The dynamic response physical process of PC detectors under sub-band gaplaser radiation is investigated. In experiment, two typical infrared detectors (PC InSband HgCdTe detector) are taken in the sub-band gap laser radiation experiment. A newphenomenon, which universally exist in the experiments of PC detectors under sub-bandgap laser radiation. The generation mechanism of the new phenomenon is thoroughanalyzed. The carrier transport model of PC detector under sub-band gap laser radiationis established. The voltage response mechanism of PC detector under sub-band gaplaser radiation is analyzed. The numerical results and experimental results are in goodagreement. It’s shown that PC detector can response to the sub-band gap laser and theresponse mechanism is only thermal effect. The thermal effects are composed oftemperature-dependence mobility effect and temperature-dependence carrierconcentration effect. The temperature of the detector increased during the sub-band gaplaser radiation process. A critical temperature T0exists in this process, which istemperature corresponding to the minimum of the electrical conductivity.When thetemperature of the detector, T, is lower than T0, the dominant mechanism istemperature-dependence mobility effect. The output voltage signals increase with thetemperature. When the T is higher than T0, the dominant mechanism istemperature-dependence carrier concentration. The output voltage signals decrease withthe temperature. The output voltage signals of the detector are decided bytemperature-dependence mobility effect and temperature-dependence carrierconcentration effect.4. The response mechanism of PV detector under sub-band gap laser radiation isinvestigated. It’s shown that the dominate response mechanism of PV detector undersub-band gap laser radiation is thermovotage. The influence of output voltage signalswith different initial open-circuit voltage is analyzed. The Si solar cells are used toreproduce the experimental results of HgCdTe detector under sub-band gap laserradiation. The experiments are designed to demonstrate the existence of thermovoltage,the difference and relationship of thermovolatge and photovolatge, and the difference ofthermovoltage and thermoelectric voltage. The trueness of thermovolatge isdemonstrated from experiment.更多还原